Add Rock Jack Writing

Font Project Git Repo URL: https://github.com/eifetx/Rock-Jack-Writing-

Super short description of the Font Family:
Rock Jack Writing are a type of digital typeface that simulates the look and feel of actual handwriting. These fonts are designed to mimic the unique characteristics of handwriting, such as the subtle variations in stroke width, the tilt and slant of individual letters, and the natural irregularities of pen or pencil marks.

**Requirements:**

I understand that Google Fonts will publish only fonts that matches its requirements, and I can confirm the project meets them (by ticking the cases, or putting x between the square brackets in text mode):

- [x] The entire font project is licensed under the [OFL](https://scripts.sil.org/cms/scripts/page.php?site_id=nrsi&id=OFL)
- [x] There is no "Reserved Font Name" mention in the OFL license
- [x] Family name is unique according to namecheck.fontdata.com
- [x] The font supports at least [GF Latin Core glyphset](https://github.com/googlefonts/glyphsets/tree/main/GF_glyphsets/Latin/)
- [x] The repository respect the [upstream repo structure](https://googlefonts.github.io/gf-guide/upstream.html)
- [x] The source files are available in the repository
- [x] I read, agree and comply with the full [contributing requirements](https://googlefonts.github.io/gf-guide/onboarding.html)
- [x] I am the author of the font or the author agreed to this submission
- [x] I will maintain the repository

**Image:**

Attach here a pic or a screenshot of the font; one is enough, it can be few letters, to give a quick overview.